Sassanid Empire

The Sassanid Empire, also known as the Sasanian Empire, Sassanid Dynasty, Sasanian Dynasty, or Persian Empire were an Iranian dynasty that stretched from Mesopotamia to the Indus River Valley as of 363 AD. Its greatest leader was Shapur II of Persia, who defeated the Romans at the Battle of Ctesiphon in 363 and conquered many regions from the Khitans, Byzantine Empire, Sagartia, Drangiana, Arachosia, Bactria, Dahae, Khorasmii, Media Atropatene, Media, Qidri, Gerrhea, Ardhan, Kartli, Colchis, and the Artaxiad Empire.

History
The Sasanians were named for Sassan, a Persian high priest of Zoroastrianism. The Sassanids dominated southern Persia at first, but conquered the Parthian Empire in 224 and founded their own dynasty over Persia, rebuilding the empire that Darius III Codomannus had founded. By way of punitive expeditions, they defeated Arabic incursions into their land, and conquered the lands of northern India from the Rajputs, and also withstood several attacks by the Roman Emperor. King Shapur defeated Flavius Julianus at Ctesiphon in 363, costing the emperor his life, and routed a large Roman force, destroying the last attempt to invade Persia by the Eastern Roman Empire. Following this victory, Rome was forced to make peace and the Persians resorted to conquering their eastern enemies, the Khitans. The Sassanid Empire's power base increased as their empire expanded, but were halted at the Battle of Nineveh. They were eventually conquered by the Rashidun Caliphate in 651.